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CN-122028394-A - Multifunctional broadband electromagnetic wave-absorbing composite material based on bionic periodic units and multistage core-shell fillers and preparation method thereof

CN122028394ACN 122028394 ACN122028394 ACN 122028394ACN-122028394-A

Abstract

The invention discloses a multifunctional broadband electromagnetic wave-absorbing composite material based on bionic periodic units and multistage core-shell fillers and a preparation method thereof, wherein the multistage core-shell fillers are used as raw materials, and (3) adopting an impregnation technology, and impregnating the bionic periodic unit by configuring high-loss coating and impedance matching coating with different concentrations to obtain the electromagnetic wave-absorbing composite material. The invention realizes accurate gradient distribution of electromagnetic parameters in a three-dimensional space and better impedance matching, the areal density is lower than 6kg/m < 2 > at the thickness of 15-20 mm, the planar compressive strength is 2MPa, and the effective absorption bandwidth (RL < -10 dB) covers 8-18 GHz. The invention solves the contradiction between the bandwidth, thickness, weight and single function of the traditional wave-absorbing material, and is suitable for the fields of advanced stealth equipment and electromagnetic protection. The material opens up a new direction for the development of electromagnetic wave absorbing materials, and is expected to be widely applied in various fields such as national defense, communication, electronics and the like.

Inventors

  • YANG TONGSHENG
  • YANG WUBIN
  • LI FUYANG
  • LIANG HAO
  • ZHANG YUCHEN

Assignees

  • 贵州铂韬电子科技有限公司

Dates

Publication Date
20260512
Application Date
20260116

Claims (10)

  1. 1. A multifunctional broadband electromagnetic wave-absorbing composite material based on a bionic periodic unit and a multistage core-shell filler is characterized by comprising a bionic periodic unit (1), wherein the bionic periodic unit (1) is hexagonal honeycomb-shaped.
  2. 2. The preparation method of the multifunctional broadband electromagnetic wave-absorbing composite material based on the bionic periodic unit and the multistage core-shell filler as claimed in claim 1 is characterized by comprising the following steps: A1, growing a carbon nano tube (3) array on the surface of a magnetic inner core (2) in situ by a chemical vapor deposition method, and grafting metal oxide nano particles (4) on the end parts of the carbon nano tubes (3) to obtain a multistage core-shell filler; a2, preparing high-loss paint and impedance matching paint respectively by taking the multistage core-shell filler as one of the raw materials; And A3, dipping the prepared bionic periodic unit (1) by using a dipping technology through configuring high-loss coatings and impedance matching coatings with different concentrations to obtain the electromagnetic wave-absorbing composite material.
  3. 3. The preparation method of the multifunctional broadband electromagnetic wave-absorbing composite material based on the bionic periodic unit and the multistage core-shell filler as claimed in claim 2, which is characterized by comprising the following steps: b1, placing a substrate material serving as a magnetic core (2) into a fluidized bed reactor, and filling carrier gas 300-600 sccm, reducing gas 100-300 sccm and carbon source gas 100-200 sccm; B2, raising the temperature from room temperature to 100-200 ℃ at a rate of 2-8 ℃ per minute, and preserving the temperature for 1-3 hours to obtain CIP@VACNTs for generating the carbon nanotubes (3) on the magnetic core (2); B3, grafting metal oxide nano particles (4) on the end parts of the carbon nano tubes (3) through a solvothermal method; And B4, alternately washing with deionized water and ethanol for 2-5 times, and vacuum drying at 40-70 ℃ for 10-15 hours to obtain the CIP@VACNTs@Fe 3 O 4 multistage core-shell filler.
  4. 4. The method for preparing the multifunctional broadband electromagnetic wave-absorbing composite material based on the bionic periodic unit and the multistage core-shell filler, as claimed in claim 3, wherein the substrate material is spherical carbonyl iron powder, the carrier gas is argon, the reducing gas is hydrogen, and the carbon source gas is ethylene.
  5. 5. The preparation method of the multifunctional broadband electromagnetic wave-absorbing composite material based on the bionic periodic unit and the multistage core-shell filler, which is disclosed in claim 3, is characterized in that the metal oxide nano particles (4) in the step B3 are Fe 3 O 4 nano particles, the grafting step comprises the steps of adding CIP@VACNTs into an ethylene glycol solution to obtain a mixed solution, adding FeCl 3 ・6H 2 O and sodium acetate into the mixed solution, performing ultrasonic dispersion for 15-45 min, transferring into a reaction kettle, performing constant-temperature reaction for 8-15 h at 150-200 ℃, and naturally cooling to room temperature.
  6. 6. The preparation method of the multifunctional broadband electromagnetic wave-absorbing composite material based on the bionic periodic unit and the multistage core-shell filler as claimed in claim 2, is characterized in that the preparation of the high-loss coating comprises the following steps: c1, placing a multistage core-shell filler, a heat-conducting flexible polymer, a diluent and a thixotropic agent into a stirrer, and stirring for 15-40 min at a rotating speed of 1200-1700 rpm to obtain a mixture A; C2, grinding the mixture for 2-5 times until the final viscosity of the mixture A is 1 multiplied by 10 5 cP~1.5×10 5 cP; The preparation of the impedance matching paint comprises the following steps: D1, placing a multistage core-shell filler, a ball, a heat-conducting flexible polymer, a diluent and a thixotropic agent into a stirrer, and stirring for 15-40 min at a rotating speed of 1200-1700 rpm to obtain a mixture B; And D2, grinding the mixture for 2-5 times until the final viscosity of the mixture B is 7 multiplied by 10 4 cP~10×10 4 cP.
  7. 7. The method for preparing the multifunctional broadband electromagnetic wave-absorbing composite material based on the bionic periodic unit and the multistage core-shell filler, as set forth in claim 6, is characterized in that the spherical objects are glass beads with the particle size of 10-20 μm, the heat-conducting flexible polymer comprises heat-conducting silicone rubber or polyurethane, the diluent is dimethylbenzene, and the thixotropic agent is fumed silica.
  8. 8. The preparation method of the multifunctional broadband electromagnetic wave-absorbing composite material based on the bionic periodic unit and the multistage core-shell filler as claimed in claim 2, wherein the bionic periodic unit (1) is immersed in the step A3, the high-loss coating is used as an innermost layer (101), the impedance matching coating is used as an outer layer (102), and the immersion is sequentially carried out.
  9. 9. The preparation method of the multifunctional broadband electromagnetic wave-absorbing composite material based on the bionic periodic unit and the multistage core-shell filler as claimed in claim 8, wherein the impregnation process step of the electromagnetic wave-absorbing composite material comprises the following steps: E1 pretreatment Washing the bionic periodic unit (1) by deionized water; The cleaned bionic periodic unit (1) is put into drying equipment for pre-drying; E2 impregnating operation Placing the pretreated bionic periodic unit (1) into an impregnation tank; slowly adding the prepared high-loss coating into the dipping tank as dipping liquid, wherein the adding amount of the dipping liquid is based on immersing 2/3 of the bionic periodic unit (1); The bionic periodic unit (1) is soaked in the soaking liquid for 30-60 min; e3:post-treatment After the soaking is finished, taking the bionic periodic unit (1) out of the soaking tank, and removing superfluous soaking liquid on the surface by adopting a draining mode; placing the drained bionic periodic unit (1) into drying equipment for drying; And E4, cooling the dried bionic periodic unit (1), controlling according to the parameters of the step E3 after cooling to room temperature, and then dipping the rest 1/3 part of the other side of the bionic periodic unit (1) with the impedance matching coating to obtain the electromagnetic wave-absorbing composite material.
  10. 10. The method for preparing the multifunctional broadband electromagnetic wave-absorbing composite material based on the bionic periodic unit and the multistage core-shell filler as claimed in claim 9, wherein the impregnation process step of the electromagnetic wave-absorbing composite material comprises the following steps: E1 pretreatment Washing the bionic periodic unit (1) by deionized water for 5-10 min, wherein the washing pressure is controlled to be 0.2-0.3 MPa; The cleaned bionic periodic unit (1) is put into drying equipment for pre-drying, the pre-drying temperature is 60-80 ℃, and the time is 1-2 hours; E2 impregnating operation Placing the pretreated bionic periodic unit (1) into an impregnation tank; slowly adding the prepared high-loss coating into the dipping tank as dipping liquid, wherein the adding amount of the dipping liquid is based on immersing 2/3 of the bionic periodic unit (1); starting vacuum equipment, vacuumizing the dipping tank, wherein the vacuum degree is controlled to be-0.085 MPa to-0.095 MPa, and the air pumping time is 15-30 min; after the vacuumizing is finished, closing the vacuum equipment, and keeping the bionic periodic unit (1) immersed in the immersion liquid for 30-60 min, wherein the immersion liquid is stirred in the immersing process at the stirring speed of 50-100 r/min, so that the concentration of the immersion liquid is ensured to be uniform; e3:post-treatment After the soaking is finished, taking the bionic periodic unit (1) out of the soaking tank, and removing redundant soaking liquid on the surface in a draining mode, wherein the draining time is 5-10 min; placing the drained bionic periodic unit (1) into drying equipment for drying, wherein the drying temperature is 80-120 ℃ and the drying time is 2-4 hours; And E4, cooling the dried bionic periodic unit (1), controlling according to the parameters of the step E3 after cooling to room temperature, and then dipping the rest 1/3 part of the other side of the bionic periodic unit (1) with the impedance matching coating to obtain the electromagnetic wave-absorbing composite material.

Description

Multifunctional broadband electromagnetic wave-absorbing composite material based on bionic periodic units and multistage core-shell fillers and preparation method thereof Technical Field The invention belongs to the technical field of electromagnetic wave-absorbing composite materials, and particularly relates to a multifunctional broadband electromagnetic wave-absorbing composite material based on a bionic periodic unit and a multistage core-shell filler and a preparation method thereof. Background With the rapid development of modern electronic information technology, the technical fields of fifth-generation mobile communication technology, radar detection, electronic countermeasure and the like are rapidly improved. In the application of these technologies, the rational control and utilization of electromagnetic waves becomes critical. 8-18GHz (X/Ku wave band) is used as a core frequency band of a radar guidance system, a satellite communication system and the like, and the requirement for efficient wave-absorbing materials of the frequency band is urgent. The wave-absorbing materials can be classified into dielectric loss type and magnetic loss type according to the electromagnetic wave loss mechanism. The existing wave-absorbing material mainly depends on ferrite, conductive carbon materials (such as carbon nano tubes and graphene) or simple physical mixture thereof as an absorbent, and is prepared by adopting a coating or laminating process. However, these conventional approaches suffer from a number of inherent drawbacks that are difficult to overcome: the electromagnetic wave attenuation capability mainly comes from a magnetic loss mechanism, the dielectric loss is insufficient, the impedance matching is poor, the electromagnetic wave attenuation capability is mostly of a solid structure, the density is high, and the electromagnetic wave loss efficiency is low. From the structural aspect, better impedance gradual matching is difficult to realize, and interlayer interface reflection is remarkable. In order to widen the bandwidth, the thickness of the material is required to be increased, which forms a sharp contradiction with the development trend of light weight and thin type of the current equipment, and severely restricts the application of the wave-absorbing material in some fields with severe requirements on weight and thickness. In the functional aspect, the traditional wave-absorbing material has single function, only focuses on absorption performance, and lacks integrated functions such as heat management, structural bearing and the like. With the development of the intellectualization and the multifunctionality of modern advanced equipment, the material with single function is difficult to meet the requirement of the material for the multifunctional composite material. The problem of the preparation level is not neglected. The traditional stirring, knife coating and mould pressing processes can not realize the precise control of components and structures of materials in a three-dimensional space, and are difficult to prepare a complex curved surface conformal structure. Meanwhile, the processes also have the problems of filler sedimentation, weak interface combination and the like, and seriously influence the performance and the service life of the wave-absorbing material. Therefore, there is a need for a wave-absorbing material that is improved from material structural design to manufacturing process, and that is both broadband and lightweight. The patent application document with the publication number of CN120573706A discloses a Fe 3 C@C assembled nano wave-absorbing structure and a preparation method thereof, wherein the surface of the nano wave-absorbing structure is provided with a C nano particle array structure and a hollow structure, so that the multiple scattering effect of electromagnetic waves is greatly enhanced, a large number of Fe 3 C-C heterogeneous interfaces promote the enhancement of the interface polarization relaxation loss effect, and the wave-absorbing performance is improved. However, the Fe 3 C@C is of a hollow sphere structure, the thickness of the wave-absorbing structure is 2.4mm, the shock resistance is weak, the Fe 3 C@C is difficult to use as a bearing structural member, and the technical problem of realizing better impedance gradual change matching is not solved by the method. Disclosure of Invention In order to solve the technical problems, the invention provides a multifunctional broadband electromagnetic wave-absorbing composite material based on a bionic periodic unit and a multistage core-shell filler and a preparation method thereof. The invention is realized by the following technical scheme. The invention provides a multifunctional broadband electromagnetic wave-absorbing composite material based on a bionic periodic unit and a multistage core-shell filler, which comprises the bionic periodic unit, wherein the bionic periodic unit is hexagonal honeyc